10 things you need to know about your gut

The bacteria in our gut, collectively known as the microbiome, is receiving a lot of attention in the science world right now, with recognition that its role in human health extends much further than just a happy tum. Let’s get up to speed with what we know so far…

1. We’re more bacteria than we are human

The gut is home to approximately 100,000,000,000,000 (100 trillion) micro organisms. That’s 10 times more than the number of cells in the human body. In fact, if you were to weigh your gut bacteria, it could weigh as much as 1.5kg.

2. Your gut controls A LOT

Keeping the microbiome balanced with a high diversity of “good” bacteria is fundamental to good health. A balanced microbiome is known to play an integral role in digestion, appetite regulation, metabolism, immunity, mood, mental health, bone development and cardiovascular health.

3. So much influences your gut health

The diversity of our gut microbiome is influenced by a number of factors including birth (natural versus caesarean-section), the environment, stress, diet and medication. It is understood that each and every one of us has a unique combination of gut bacteria comprising our microbiome. Every time we eat a meal, go outside, kiss someone or take a course of antibiotics, we are affecting the composition of our microbiome.

4. The gut microbiome population begins at birth

When a baby passes through the birth canal and picks up billions of bacteria from their mother’s vagina, the microbiome is formed. For babies born through c-section, bacteria are acquired from the hands of the medics and surrounding environment. Babies born through c-section have higher rates of of asthma, allergies and atopic disease, and this is increasingly being linked to differences in their microbiome to those born through a vaginal birth, who harbour a more diverse array of bacteria.

5. Our obsession with hygiene could be a bad thing

It used to be thought that there was no such thing as “good” microbes, and that bacteria harmed us and made us ill. As a result, we’ve been blitzing them with excessive cleanliness, antibacterial sprays, and a heavy reliance on antibiotics. The “hygiene hypothesis” suggests that by keeping ourselves too germ-free, we’ve been restricting ourselves of the bacteria necessary to keep our microbiome balanced, and this could be having a negative impact on our health, particularly our immune system.

GettyPhotoAlto/Frederic Cirou

6. It’s easy to hamper ‘good’ bacteria

There are other factors that may also contribute to an unbalanced microbiome. These include chronic stress, infections, alcohol, and a diet high in refined carbohydrates, sugar, junk food and low in fibre. These can all hamper the growth of the “good” bacteria in the gut.

7. The gut microbiome needs fuelling to keep it diverse

Probiotics are live bacteria that help balance the microbiome by replenishing it with “good” bacteria. These can be taken in a capsule form, or by consuming fermented foods such as live yoghurt, sauerkraut, kimchi, miso and kefir. It is thought to be particularly important to re-inoculate this “good” bacteria following antibiotic treatment. Prebiotics are foods that feed the “good” bacteria in the gut and include foods such as onion, garlic, cruciferous vegetables (broccoli, cabbage, cauliflower), lentils and beans. A plant-based diet rich in fresh fruits and vegetables nourishes a healthy gut microbiome.

8. Our gut helps us break down and absorb nutrients

Without it, we would lack the ability to both digest our food, and to extract the critical nutrients from it that we need to function. Certain vitamins are also synthesised by our gut bacteria, particularly the B vitamins and vitamin K. Some bacteria also produce butyrate, a compound which provides a source of energy for the colon, and is vital for the good health of the digestive tract.

9. The majority of our immune system is based in the gut

Known as GALT, gut-associated lymphoid tissue, our GALT is filled with clusters of immune cells, which are the first line defence and prevent harmful microbes from penetrating the wall of the gut and being absorbed. It is becoming increasingly understood that the human microbiome is critical to the functioning of the GALT, and that having plenty of the “good” bacteria helps to keep the “bad” bacteria in check.

10. The gut has been labelled our “second brain”

And the two are intricately linked, hence the expression, a “gut feeling”. The gut bacteria produce an array of neurochemicals that the brain uses for the regulation of memory, learning and mood. In fact, at least 80% of our body’s “happy hormone” serotonin is synthesised by our gut bacteria. It has been hypothesised that modifying our gut bacteria could influence anxiety and depression, and this is an area of much ongoing research.